Nissan Forum banner
1 - 13 of 13 Posts

·
Registered
Joined
·
126 Posts
Discussion Starter · #1 ·
Any car with height-adjustable struts/springs.

Does the weight distribution change if, say, the rear end only is lowered?

Is there any weight transfer towards the back due to relocation of the Center of gravity?

Chris
 

·
Registered
Joined
·
547 Posts
I would say that it does. Because think about it this way...if you lower the front of the car and take a corner too fast, your ass end would fly around. And it would do it more severly if your ass end was higher. That's just what I would think. I can try if you want?!? JK. And if the front end was higher...you would gain ZERO traction if you tried to launch or race someone. I would also guess that you brakes would not do that great of a job either.
 

·
Registered
Joined
·
185 Posts
The other Bob said:
The simple answer is no.
You can't change the total weight on the front,rear or sides of the car without physicaly moving weight(ballast or moving the battery to the trunk etc)
You can change the corner weight (diagonal) with adjustable coil-overs though.
Here's a link that can help http://www.grassrootsmotorsports.com/cornerweight.html
HORSEPUCKY

The answer is an emphatic yes. Somebody at GRM was typing with a banana. I've done it and seen it with my own two eyes. Sometimes I think the boys at GRM get bananas delivered daily.
 

·
Registered
Joined
·
185 Posts
The other Bob said:
I beg to differ George...read the last paragraph and insert the words "Front, Rear, Leftside or Rightside"
Like it say's "you can turn the jack screws all day and it won't change"
http://www.rebcoperformance.com/articles/art.asp?ARTID=1
You know what Bob, I don't give a rat's ass what GRM says or Rebco says. BTW, my understanding is that adjusting weight jackers and adjusting coilovers are not the same thing.

Have you ever done any of this yourself?

FWIW, I had a similar conversation last year at Texas World Speedway when we went to corner weight our SCCA ITS Sentra SE-R. I read the original article on the subject of weight jacking not affecting F/R weight distribution back in Stock Car Racing magazine back about 22-23 years ago. It was written by Will Cagle, the dean of dirt track modifieds in the northeast.

OK, jump back to last year. I brought this up and was also told it was different because oval trackers use weight jackers. We then went about corner weighting the car. Adjusting one corner along did indeed affect all 4 corners. Furthermore, it did indeed affect total front to total rear weight as well as side to side.

Try it.
 

·
Registered
Joined
·
6 Posts
Quote:
Have you ever done any of this yourself?

Yeah George,I've done plenty of this myself on my own cars and alot of customers & friends cars,from street cars to Nascar pavement modifieds and everything in between.
I sponsor an S/K Modified @ Stafford Motor Speedway
#16 Davidson Foods/Performance Centers
Driven by Wayne Bellefleur (sadly sidelined for 02 due to a brain tumor but, after the surgery he's finally been given the green light from the doctors for 03!!!! )
The best I could find for pic's are these:
http://www.petesracingsite.com/2001/Carquest_SK_LM_2001/
http://www.skmods.com/ol/mc2001.htm
And yes "Performance Centers" is my shop located here in East Hartford Connecticut
Stop by if you're ever "in the neighborhood"
We seem to have a Sentra/NX2000/240sx thing goin' on here lately...about 10 SR20de/sr20det powered cars

Quote:
We then went about corner weighting the car. Adjusting one corner along did indeed affect all 4 corners. Furthermore, it did indeed affect total front to total rear weight as well as side to side

Yes I'm sure it affected all 4 corners but, the "weight percentages" (total front, total leftside etc.)for the front,rear,left or right didn't change.
If they did you may want to have your scales checked.
The only possibility would be fuel load shifting in the fuel cell/gas tank but of coarse, the amount from that would be minimal I'm sure.

Quote:
You know what Bob, I don't give a rat's ass what GRM says or Rebco says. BTW, my understanding is that adjusting weight jackers and adjusting coilovers are not the same thing.

Well you're partially correct...They are 2 different things.
They do the same job with the same results though.
"Weight jackers" are a threaded rod that is fixed to the chassis where the end sits on the spring to adjust it, while a "coil-over" is a nut that's threads on a shock or strut that adjusts the spring.
They both adjust load on the spring & chassis hight.

Quote:
I read the original article on the subject of weight jacking not affecting F/R weight distribution back in Stock Car Racing magazine back about 22-23 years ago. It was written by Will Cagle, the dean of dirt track modifieds in the northeast.

'Ya know what ? I think my dad knew this guy,my father raced dirt track modifieds from the late 50's to late 70's.'til he made the switch to pavement...still racing too at 66 yrs old, albeit in a "Legends" car now that he's "retired"
I've been to so many dirt tracks in New England when I was a kid my mom thought I'd never come clean...haha

Sorry for the long post
 

·
Registered
Joined
·
185 Posts
The other Bob said:
Yeah George,I've done plenty of this myself on my own cars and alot of customers & friends cars,from street cars to Nascar pavement modifieds and everything in between.
I sponsor an S/K Modified @ Stafford Motor Speedway
Stafford? Way cool! Do the Supermodifieds still come there? I grew up in Rochester, NY and 20 years ago used to go to Oswego all the time. Sometime I hope to get back to Rochester in the summer so I can go to another race at Oswego. God, I love that place. I'm not much into circle track racers anymore, but I absolutely adore Supermodifieds and really like Midgets. BTW, have you seen this month's issue of Racecar Engineering? They have an article on the ISMA Supers.

The other Bob said:
#16 Davidson Foods/Performance Centers
Driven by Wayne Bellefleur (sadly sidelined for 02 due to a brain tumor but, after the surgery he's finally been given the green light from the doctors for 03!!!! )
Oh God, I'm so sorry to hear about the brain tumor. I'm so glad the outcome. Godspeed.

The other Bob said:
And yes "Performance Centers" is my shop located here in East Hartford Connecticut
Stop by if you're ever "in the neighborhood"
We seem to have a Sentra/NX2000/240sx thing goin' on here lately...about 10 SR20de/sr20det powered cars
Yeah, I know Hartford has plenty of SR20 powered cars around there. I met a bunch of the guys there a couple of years ago when I met up with them at Acceleration Pluss. I drove Craig Damashi's SE-R at the 01 SE-R convention. Without a doubt it was the best rotating SE-R I've ever driven, including our racecar.

I used to get up to the area on a somewhat regular basis for work (I used to be the Inventory Accounting Manager for Big A Auto Parts), but the company sold out. My sister lives in the next town over from Milford, MA, but she's selling her house and moving to Dallas. So.... I don't know when I'll get up in the neighborhood again, but rest assured, if I'm in the neighborhood, I'll be stopping in.

Do you know Bob Legere?

The other Bob said:
Yes I'm sure it affected all 4 corners but, the "weight percentages" (total front, total leftside etc.)for the front,rear,left or right didn't change.
I'm 95% sure they did. I don't have the data here so I cannot confirm it. But, I am pretty sure I double checked that because of the aforementioned Will Cagle article and I wanted to check that the info I was getting from others to the contrary was correct.

The other Bob said:
If they did you may want to have your scales checked.
The only possibility would be fuel load shifting in the fuel cell/gas tank but of coarse, the amount from that would be minimal I'm sure.
I guess that's possible. The shift wasn't terribly large as I recall. But, like you, I think the effect of fuel slosh would be minimal.

The other Bob said:
Well you're partially correct...They are 2 different things.
They do the same job with the same results though.
"Weight jackers" are a threaded rod that is fixed to the chassis where the end sits on the spring to adjust it, while a "coil-over" is a nut that's threads on a shock or strut that adjusts the spring.
They both adjust load on the spring & chassis hight.
Thanks for the explanation. I never knew how a weight jacker worked.

The other Bob said:
'Ya know what ? I think my dad knew this guy,my father raced dirt track modifieds from the late 50's to late 70's.
What's his name? I followed those cars through the late 70s and basically knew a lot of the names in the northeast. I would bet your dad did know Will Cagle. They were of the same era. Cagle stopped racing in the mid to late 70s. I think I saw him race once. He was the hot shoe of the DIRT circuit when it was just starting out.

The other Bob said:
'til he made the switch to pavement...still racing too at 66 yrs old, albeit in a "Legends" car now that he's "retired"
I've been to so many dirt tracks in New England when I was a kid my mom thought I'd never come clean...haha
Hehe. That's cool that he's still racing.

The other Bob said:
Sorry for the long post
Hey, mine's even longer. :)

I'll try to get a hold of that data from when we corner weighted the car and post it. It might take a while since Grover (the car owner) has a newborn and it will likely be the last thing on his mind. You've got me rethinking, but like I said, I remembered that article and argued exactly what you are saying an my recollection is that I was proven wrong.
 

·
Registered
Joined
·
185 Posts
Thread hi-jack in process

Bob, what a great trip down memory lane this thread is bringing me (and I'm hi-jacking the thread :D ).

Do you know or know of any of the following people:

Dan Schum

http://www.speedwayad.com/branichmod/news0001.htm

Dan, his son Scott, and his late wife Debbie took me under their wing when I started racing karts in 87. Great folks. If you ever run into him, please please, please tell him I said hi.

Todd Burley

http://www.bluemoon.net/~rg23/burley.htm

I used to race karts at the same track as Todd. He raced more with Scott Schum and probably wouldn't remember me, but we had some of the same friends. Todd raced for Dan in his pavement modified at Lancaster after Dan's son Scott gave up racing. Todd mostly races dirt modifieds.

Kent Peckham - I don't have any good links for him. He raced dirt modifieds for a while. Best I can tell he is no longer racing and is working for a NASCAR team. If you remember a couple of years ago at The Glen they had an in-car camera on a car that hit a tire changer during a pit stop. The tire changer that was hit was Kent. I also raced karts with him.

Dang Bob. This has been fun. Fond memories.

Oh and BTW, while looking up some of this I found out that Will Cagle's last win at Canandiagua came in 85.

BTW, I love the asphalt modifieds on the east coast. Much better than the stuff we find here.

I guarantee if I am in your area I will look you up.
 

·
Registered
Joined
·
6 Posts
George, the ISMA Supermods haven't been to Stafford in years but they still race @ Thompson(fastest speedway in Connecticut) as do the NEMA Midgets.
Yeah! I hear 'ya! Nothing like an alchy injected big block w/18" wide rubber and a big wing to get 'ya movin and the midgets come off the corner at about 90mph with the front wheels up!...I'd love to get behind the wheel of 1 of these!!!
Racecar Engineering...I let my subscription lapse:(

You know Craig Damshi? (aka phsyco)...yeah I know most all of the "Nissan guys"...good people.
Bob Legere too...friends from long ago.
I'll bet there's about 6 or 8 guys that frequent this board and hang out at my shop.
Seems as if the current plan from all the guys that hang out @ the shop is to turbocharge every Nissan in the area...so far it's working:D

My fathers name Bob Leach (same as mine ;)
Started racing the #16 then the 3, M3, 103, then drove for Arnold Fluery in # 52 for a few years and drove for Roy Messick then back to driving his own cars...oh hell he's been racing longer than I am old! and I'm 40.
He's built & sold more cars than I can count

Back to the subject,I'm going to scale a car tomorrow and I'll post the results then...I need sleep!
 

·
Registered
Joined
·
185 Posts
The other Bob said:
You know Craig Damshi? (aka phsyco)...yeah I know most all of the "Nissan guys"...good people.
Bob Legere too...friends from long ago.
I'll bet there's about 6 or 8 guys that frequent this board and hang out at my shop.
Heck yeah, I know most all those guys. Jay Hassinger, Matt Niaura, and a few others. Makes me wonder if you weren't there when we all went to Hooters a couple of years ago when I was there.

BTW, what's Jay up to these days? I've been meaning to write to him to find out.

The other Bob said:
Seems as if the current plan from all the guys that hang out @ the shop is to turbocharge every Nissan in the area...so far it's working:D
Sounds about right. :)

The other Bob said:
My fathers name Bob Leach (same as mine ;)
Started racing the #16 then the 3, M3, 103, then drove for Arnold Fluery in # 52 for a few years and drove for Roy Messick then back to driving his own cars...oh hell he's been racing longer than I am old! and I'm 40.
He's built & sold more cars than I can count
Sounds very familiar.

The other Bob said:
Back to the subject,I'm going to scale a car tomorrow and I'll post the results then...I need sleep!
Hehe. I know what you mean about the sleep. I have too many things going on in my head (and they ain't no damned sugar plums ;) ). I'm trying to get new products out of my head, on the drawing board or into CAD, get prototypes done, and get them into production. The problem is, the ideas keep coming faster than I can get things done. :)
 
G

·
not to interrupt this mindless drivel, but your answer is yes and no...

No, the weight distribution of the car remains the same (probabally 50/50 if you have a skyline or 240sx), as no parts are changing positions within the car.

However...
Yes, handling characteristics of the car will change, due to the fact that a higher proportion of the weight is focused on the lower end. You can probabaly visualize this if you think about the car being so low in the front, for instance, and the back being jacked up so that there is almost no load on the rear wheels. This would give the same effect as brake dive, with the back end acting as if it were lighter, when in reality it still weighs the same with the weight merely being loaded on to the front of the car instead of the rear...
You can also think of it as if your car were going down a steep hill--the front wheels are taking more of the load than the rear wheels, even though there has been no physical change in the car's weight distribution.

If this explaination doesn't make sense, I'll try to come up with one that does. Hope it helps
-MR
 

·
Registered
Joined
·
185 Posts
mranlet said:
No, the weight distribution of the car remains the same (probabally 50/50 if you have a skyline or 240sx), as no parts are changing positions within the car.
Have you ever corner weighted a car?

As I said earlier, I have, and as we adjusted it, F/R distribution did indeed change. I don't have the data with me here as it's with the car owner in Dallas, but I will be bringing the car back to Houston for my race in January and I will try to get that data when I pick it up.

mranlet said:
You can probabaly visualize this if you think about the car being so low in the front, for instance, and the back being jacked up so that there is almost no load on the rear wheels. This would give the same effect as brake dive, with the back end acting as if it were lighter, when in reality it still weighs the same with the weight merely being loaded on to the front of the car instead of the rear...
Static weight distribution is a different issue from load transfer.
 
1 - 13 of 13 Posts
Top